It is possible to set permissions for EMC
PowerPath devices to be persistent across server reboots and EMC PowerPath
restarts.
This can be achieved through UDEV Rules.
For Oracle Cluster Ready Services (CRS) the
permissions on devices supporting the OCR and Voting disk are essential for CRS
to function.
Edit the /etc/udev/rules.d/50-udev.rules file and add the text below (where
“emcpowerb” is the Voting disk and “emcpowerc” is the OCR)
#
emc block devices
# Voting
SUBSYSTEM==”block”, KERNEL==”emcpowerb”, GROUP=”oinstall”, OWNER=”oracle”,
MODE=”0640″
#
OCR
SUBSYSTEM==”block”, KERNEL==”emcpowerc”, GROUP=”oinstall”, OWNER=”root”,
MODE=”0640″
The voting disk is a partition that Oracle
Clusterware uses to verify cluster node membership and status.
The voting disk must be owned by the oracle
user, must be in the dba or oinstall group, and must have permissions set to
644
The location of the Voting disk may be found
by executing the following command as root user:
<CRS_HOME>/bin/crsctl
query css votedisk
E.g.
/u01/app/oracle/product/11.1.0/crs/bin/crsctl
query css votedisk
The OCR disk supports the Oracle Clusterware
Registry, which holds the complete configuaration of the cluster.
This includes metadata for nodeapps, ASM
instances, database instances, database listeners, databases etc.
The OCR location may be found in /etc/oracle/ocr.loc
emcpower* devices are pseudo device names
created by EMC PowerPath.
It is also possible to add the following
text to /etc/init.d/init.crs file to enable persistence.
chown
root:oinstall /dev/emcpowerc
chown
oracle:oinstall /dev/emcpowerb
However, root.sh will overwrite this file
when performing a CRS upgrade. Therefore the /etc/init.d/init.crs file should not be modified.
It is essential that EMC PowerPath pseudo device names are consistent between nodes in a cluster. Also the name must be persistent across server reboots. Below are commands with example output that help to illustrate the ease of device management from the Linux command line.
The following EMC PowerPath Management command displays the state of all the HBAs configured for PowerPath:
[root@#####01A
~]# powermt display dev=all
Pseudo
name=emcpowerh
Symmetrix
ID=000290104687
Logical
device ID=04C5
state=alive;
policy=SymmOpt; priority=0; queued-IOs=0
==============================================================================
----------------
Host --------------- - Stor - -- I/O Path - -- Stats ---
### HW Path I/O Paths Interf.
Mode State Q-IOs Errors
==============================================================================
2 lpfc sdd FA
3cB active alive
0 0
0 lpfc sdm FA 14cB
active alive 0
0
Pseudo
name=emcpowerg
Symmetrix
ID=000290104687
Logical
device ID=04CD
state=alive;
policy=SymmOpt; priority=0; queued-IOs=0
==============================================================================
----------------
Host --------------- - Stor - -- I/O Path - -- Stats ---
### HW Path I/O Paths Interf.
Mode State Q-IOs Errors
==============================================================================
2 lpfc sde FA
3cB active alive
0 0
0 lpfc sdn FA 14cB
active alive 0
0
Pseudo
name=emcpowerf
Symmetrix
ID=000290104687
Logical
device ID=04D5
state=alive;
policy=SymmOpt; priority=0; queued-IOs=0
==============================================================================
----------------
Host --------------- - Stor - -- I/O Path - -- Stats ---
### HW Path I/O Paths Interf.
Mode State Q-IOs Errors
==============================================================================
2 lpfc sdf FA
3cB active alive
0 0
0 lpfc sdo FA 14cB
active alive 0
0
Pseudo
name=emcpowerc
Symmetrix
ID=000290104687
Logical
device ID=04DD
state=alive;
policy=SymmOpt; priority=0; queued-IOs=0
==============================================================================
----------------
Host --------------- - Stor - -- I/O Path - -- Stats ---
### HW Path I/O Paths Interf.
Mode State Q-IOs Errors
==============================================================================
2 lpfc sdg FA
3cB active alive
0 0
0 lpfc sdp FA 14cB
active alive 0
0
Pseudo
name=emcpowerb
Symmetrix
ID=000290104687
Logical
device ID=04E5
state=alive;
policy=SymmOpt; priority=0; queued-IOs=0
==============================================================================
----------------
Host --------------- - Stor - -- I/O Path - -- Stats ---
### HW Path I/O Paths Interf.
Mode State Q-IOs Errors
==============================================================================
2 lpfc sdh FA
3cB active alive
0 0
0 lpfc sdq FA 14cB
active alive 0
0
Pseudo
name=emcpowera
Symmetrix
ID=000290104687
Logical
device ID=04ED
state=alive;
policy=SymmOpt; priority=0; queued-IOs=0
==============================================================================
----------------
Host --------------- - Stor - -- I/O Path - -- Stats ---
### HW Path I/O Paths Interf.
Mode State Q-IOs Errors
==============================================================================
2 lpfc sdi FA
3cB active alive
0 0
0 lpfc sdr FA 14cB
active alive 0
0
Pseudo
name=emcpowere
Symmetrix
ID=000290104687
Logical
device ID=05FD
state=alive;
policy=SymmOpt; priority=0; queued-IOs=0
==============================================================================
----------------
Host --------------- - Stor - -- I/O Path - -- Stats ---
### HW Path I/O Paths Interf.
Mode State Q-IOs Errors
==============================================================================
2 lpfc sdb FA
3cB active alive
0 0
0 lpfc sdk FA 14cB
active alive 0
0
Pseudo
name=emcpowerd
Symmetrix
ID=000290104687
Logical
device ID=05FE
state=alive;
policy=SymmOpt; priority=0; queued-IOs=0
==============================================================================
----------------
Host --------------- - Stor - -- I/O Path - -- Stats ---
### HW Path I/O Paths Interf.
Mode State Q-IOs Errors
==============================================================================
2 lpfc sdc FA
3cB active alive
0 0
0 lpfc sdl
FA 14cB active alive
0 0
The following command lists all used PowerPath pseudo device names:
[root@#####01A
~]# emcpadm getusedpseudos
PowerPath
pseudo device names in use:
Pseudo
Device Name Major# Minor#
emcpowera 120 0
emcpowerb 120
16
emcpowerc 120
32
emcpowerd 120
48
emcpowere 120
64
emcpowerf 120
80
emcpowerg 120
96
emcpowerh 120
112
The following command lists available PowerPath pseudo device names:
[root@#####01A
~]# emcpadm getfreepseudos
Next
free pseudo device name(s) from emcpowera are:
Pseudo
Device Name Major# Minor#
emcpoweri 120
128
On Linux, EMC PowerPath configuration settings are stored in
config file /etc/powermt.custom
To rename an existing PowerPath pseudo device name to an available pseudo device name, issue the following command with source and target names.
[root@#####01A
~]# emcpadm renamepseudo -s emcpowerg -t emcpoweri
To save changes made issue the following command:
[root@#####01A
~]# powermt save
By default, powermt
save saves the PowerPath settings in the file powermt.custom
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